Aplomado falcon (Falco femoralis)

Classified as Least Concern (LC) on the IUCN Red List (1) and listed on Appendix II of CITES (3).

Spanish for lead-coloured, the aplomado falcon’s common name is a reference to the adult’s blue-black upperparts (2). A slim-bodied raptor with longish wings and tail, the aplomado falcon has distinctive head markings, comprising a white band running above the eyes, meeting at the back of the head. This band is bordered below by a black stripe extending back from the side of the eye, below which the cheeks and throat are buff or white with a second black stripe running downwards from the base of the bill. The primary feathers and tail are blackish, with the latter marked conspicuously with a white tip and five or six thin white bars. The chest is cream to pale reddish-brown, often with short blackish streaks, and separated from the darker yellowish or rufous belly by a dark blackish, horizontal band flecked with white (4).

There are three subspecies of the aplomado falcon, which can be distinguished by location and appearance. Falco femoralis femoralis is the smallest subspecies, and is browner-grey above with a darker crown; Falco femoralis pichinchae is dark slate-grey above and richer rufous below, with a divided blackish breast band; while Falco femoralis septentrionalis has paler blue-grey upperparts (4).

Although the aplomado falcon is extremely widely distributed, it is generally uncommon and its range is fragmented. It can be found throughout South America, with the exception of the Amazon basin, as well as parts of Central America (4). Prior to the 20th century the aplomado falcon’s range also extended north to southernmost North America, but following habitat alteration, it gradually disappeared from this region. However, thanks to restoration efforts, a small self-sustaining population now exists in southern Texas (4) (5).

The aplomado falcon occupies a range of open habitats, including savanna, scrubland, grassland, cactus desert, and marshland, inhabiting a range of altitudes from lowlands to high-altitude areas of the Andes, up to 4,600 metres above sea-level (4).

A swift and agile flier, the aplomado falcon employs a variety of hunting techniques and takes a wide range of prey. At dawn, it generally hunts birds by making a quick dash from a perch and chasing them through the air. At dusk, however, this species more commonly feeds on airborne insects such as beetles, which it catches on the wing, and will also snatch rodents, lizards and small snakes from the ground. Interestingly, aplomado falcon breeding pairs assist one another in hunting, with the female flushing birds from vegetation while the male flies overhead (4). This generally results in improved hunting success and enables the pair to take larger prey (2) (4).

The aplomado falcon’s breeding season varies according to location, breeding between February and August in Mexico, September and January in central Argentina, and November onwards in Chile. It generally uses old, unoccupied nests of other raptors, or occasionally a natural ledge formed by epiphytes growing on trees, shrubs or cacti. The female lays a clutch of two or three eggs, which are incubated for around one month, fledging around 30 to 35 days later (4).

Although generally uncommon, the extremely wide distribution of the aplomado falcon means that it has a relatively large global population (4). Nevertheless, declines are apparent throughout this species’ range, and it is listed by the U.S. Fish and Wildlife Service as Endangered (4) (6).

The historical decline and eventual extirpation of the aplomado falcon that occurred in southern U.S.A. was believed to have been driven by changes made to this species’ habitat following the Spanish invasion and the intensive grazing that occurred during the late 1800s. Today, this species remains threatened by habitat loss, and possibly by the use of pesticides (4). In particular, the small population of this species in Chihuahua, Mexico is under threat of extinction due to conversion of native grasslands to farmland (5).

The Peregrine Fund started reintroducing captive-bred Aplomado falcons into southern Texas in 1993, which today have successfully formed a self-sustaining population. The organisation is now working to re-establish this species in west Texas and southern New Mexico, thereby helping to reinstate this species as an important component of the local environment. It has also helped to secure more than 8,000 square kilometres of suitable habitat from landowners, which should greatly assist recovery efforts and help to achieve the organisation’s goal of removing the aplomado falcon from the U.S. Endangered Species List within the next decade (5).